Station number identifier



March 20, 1956 w. H. T. HOLDEN4 STATION NUMBER IDENTIFIER 4 Sheets-Sheet l Filed Jm` 6, 1953 kmf /M/E/v To@ W h'. 7.' HOL DEN A T TURA/EV w. H. T. HOLDEN 2,739,187

STATION NUMBER IDENTIFIER 4 Sheets-Sheet 2 March 20, 1956 Filed Jan. e, 1953 A 7' TORNE V W. H. T. HOLDEN STATION NUMBER IDENTIFIER March 20, 1956 4 Sheets-Sheet 3 Filed Jan. 6, 1953 vl/EN To@ W H. 7.' HOLDEN A T TOR/VE? March 20, 1956 Filed Jan. 6, 1953 FIG. 4

w. H. T. HOLDEN 2,739,187

STATION NUMBER IDENTIFIER 4 Sheets-Sheet 4 A 7` TORNEV i equipment.

United States Patent O STATION NUMBER DENTIFIER Application January 6, 1953, Serial No. 329,912 7 Claims. (Cl. 179-118) This invention pertains to telephone systems which are provided with means for identifying calling station directory numbers, and pertains especially to improvements over the system for identifying such numbers which is disclosed in Patent No. 2,484,612 issued on October 1l, 1,949 'to Joseph W. .Dehn and William H. T. Holden.

Calling line identifying devices are necessary whenever `items of information pertaining to telephone calls, and including the identity of the stations from which such calls are placed, are to be automatically recorded. For this purpose it is often desirable in the first instance to identify the calling stations by their directory numbers rather than by their terminal numbers, in order to avoid thereby subsequent additional operations to obtain, `for billing purposes, the former numbers from the latter. Identification of `lines (or stations) by their directory numbers presents diiiiculties, particularly in vtelephone systems of the cross-bar type, for example, where the relation between the numbers indicating the terminating locations of the lines in the oflice (terminal numbers) and the directory numbers of the stations located on the line terminals is purely arbitrary.

The kpresent invention discloses an economical and simple arrangement for obtaining the directory `numbers of calling stations directly and rapidly. While particularly valuable for use with cross-bar telephone systems, it is not limited in use to such systems, nor `to the purposes of automatic message recording, but is applicable to any type of telephone system and for any purpose for which the determination of the directory numbers of lines or stations is desirable.

A feature of this invention is a station number identifier `that uses electronic devices which are inexpensive, readily replaceable and not subject to rapid deterioration.

Another feature of the invention is the use of a unidirectional pulse of extremely short duration to effect the operation of devices which identify the number of .the calling station, with consequent economics in time, and

' The pulse may be of extremely short duration since the ,indicating devices responsive `to the pulse are affected `by the Vrate of change of the pulse as ,it in creases from zero to its maximum value as well as by thc specic magnitude of the pulse.

lAnother feature of the invention is an arrangement whereby a number of identifiers may be severally counected to different stations to identify the respective directory numbers of `acid stations without said identifier interfering with one another.

One feature of the identifier which constitutes ya part of the present `invention is its ability vto identify onel or the other of two directory numbers associated, respectively, with one and the other of two stations on -a party line, without the need of a number field for the `stations `on the tip conductors of the lines and a similar nurnber field for the stations on the ring conductors.

A more specific feature of the `identifier constituting apart of Vthe present invention is the use of two time slots (time-spaced impulses) for identifying individual QJS? llatented Mar. 20, 1956 to identify individual stations and ring stations of twoparty lines, and the other time slot being used to identify tip stations on such two-party lines.

Still another feature of the invention is the adaptation of equipment to serve a large number of subscribers lines, not only in one central ofce but, if desired, in a plurality of such oiiices. l rhese and other features of the invention will be the more readily understood from the following description, appended claims, and the drawing in which:

` Fig. 1 shows two subscribers lines, a twoparty`liue .and an individual line, the extension` of said` two-party line by switching means including a portion of theV out going trunk, and a portion or' the common circuit networks provided for identifying the directory numbers of the stations on said lines and on other lines;

Fig. 2 shows another portion of the common circuit networks;

Fig. 3 shows the circuit of an identifier;

Fig. 4 shows the circuit for actuating a plurality of identifiers;

Fig. V5 is a graphical representation of the potentials supplied to the pulse generating tube 74 shown in Fig. `4,; and

Fig. 6 shows how the above figures (except Fig. 5) should be placed with relation `to one `another to disclose the invention.

i will rst describe the arrangement of the common circuit networks provided for identifying `calling station numbers, from which description the general mode of operating the invention will be apparent. For purposes of illustration, two subscribers lines llt and 12 are shown in Fig. l; line lli being a two-party line with ring station A thereon having the directory number 523 8, and a tip station C having directory number 0099 While line 12 is an` individual line with station B `thereon having di.- rectory number 4167. As is well known, the station on an1individual line is treated, electrically speaking, like the ring station of a two-party line, in. that the party identification test for a `calling ringV station on atwo-.party line is the same as for a Vcalling single station `on an rindividual line. lt is assumed that both `of the abovementioned lines are in the same central ofce.

In accordance with the present invention, the sleeve conductor of each line having one or two stations thereon, 'each having a directory number to be identied when the station calls, is connected to one element of each of two or four gas discharge, three-element, cold cathode tubes; there being one pair of such tubes provided for n each of the stations on the line. For example, the vsleeve conductor 13 of line il is connected through resistors 15' and 1,6 to the starter anode of each of the tubes 15 and 16, respectively, provided for the ring station A; and through resistors l and ld to the starter anode of each of the tubes lt'l and 15b, respectively, provided for the tip station C. On the other hand, the sleeve conductor 14 of line l2 is connected through resistors 17 and 18 to the starter anode of each of tubes 17 and 13., respectively, provided for the single station B on the line 12. The main anodes of the two tubes constituting each pair of tubes are connected together and extended to conductor RP or TP depending upon whether the station with which the pair of tubes is associated 4is a ring lor `a tip station, respectively. Thus, the main anodes of tubes 17 and 1d associated with the single station B lon line l2 are connected together, and by means of conductor Jil, are connected to conductor RP. This is.

also Ytrue of the main anodes of the two tubes 15 and 16 which, by means of conductor i3 are connected to conductor RP, since the station A on line l1 with which said tubes Aare associated is a ring station. On the oth- 3 er hand, the Vmain anodes of the tubes 150 and 151, associated with the tip station C on line 11, are connected by means of conductor J2 to conductor TP. This manner of connecting the main anodes of the two pairs of tubes assigned to each station in the exchange is followed for all stations; that is, the main anodes of tube pairs associated with the individual stations and ring party stations are connected to conductor RP, while the main anodes of tube pairs associated with tip party stations are connected to conductor TP. lt should be noted that conductors TP and RP extend, in part, to the outer terminals of the seco-ndaries of transformer 6th which is supplied with a full wave alternating potential from source 59, thus to produce a positive pulse on each half of a full wave for application, respectively, to conductors RP and TP.

The cathode of one of the tubes of the pair associated with each of the stations on the several lines is connected to one of 100 common conductors or bus-bars, in accordance with the thousands and hundreds digit combination of the directory number of each of said stations. For example, bus-bars 'II-100, Tiri-411, TH52 and TH99 are four of the 100 thousands-hundreds digits bus-bars TI-Iild TH99 provided for otiice No. 1 in which lines 11 and'12 are assumed to be located, and are the bus-bars assigned to the thousands and hundreds digit combina- Ktions 00, 41, 52, and 99, respectively, of the total of 10,000 directory numbers. Accordingly, the cathode of tube 15, associated with ring station A on line 11, and having the directory number 5238, is connected to busbar TH52, to which are also connected cathodes of tubes associated with other stations on other lines (not shown) in the same central office having directory numbers the thousands digit of each of which is and the hundreds digit is 2. associated with the tip station C on line 11, and having the directory number 0099, is connected to bus-bar TH00, to which are also connected with the cathodes of tubes associated with other stations on other lines (not shown) in the same central office and having directory numbers the thousands digit of each of which is 0 and the hundreds digit is 0.

`Likewise, thecathode of tube 17, associated with line 12 the directory number of whose individual station B is 4167, is connected to bus-bar T1141, to which are also connected the cathodes of tubes associated with other stations on other lines (not shown) in the same central otiice and having directory numbers the thousands digit of each of which is 4 and the hundreds digit is l.

To each of the 100 thousands-hundreds digits bus-bars THG T1199 is connected one element of each of three gas discharge cold cathode diode tubes. For example, one element of each of tubes 19, and 21 is connected to bus-bar TH99, one element of each of tubes 22, 23, and 24 is connected to bus-bar TH52, one element of each of tubes 25, 26, and 27 is connected to bus-bar TH41, and one element of each of tubes 28, 29 and 30 is connected to bus-bar THW. The other element of one of the tubes connected to each thousands-hundreds digits bus-bar is connected to a bus-bar which is individualto the central office served by said 100 thousandshundreds digits bus-bar. For example, one element of each tube 19, 22, 25, and 2.55 is connected to the bus-bar OFI-i1, which is individual to oice No. l.

The other element of the second of the tubes associated with each of the 100 thousands-hundreds digits bus-bar TH00 TH99 is connected to one of 10 thousands digit bus-bars TH@ THQ in accordance with the thousands digit of the thousands-hundreds digit combination of directory numbers, while the other element of the third tube associated with each of the 100 thousands-hundreds digits bus-bars is connected to one of l0 hundreds digit bus bars H0 H9 in accordance with the hundreds digit of the thousands-hundreds digit combination of directory numbers. For example, tube 23, one of In a similar manner, the cathode of tube 150,

whose elements is connected to bus-bar TH52 assigned to "the digit combination 52, has its other element connected to the thousands digit bus-bar THS, to which are also connected corresponding elements of tubes associated with others of the 100 thousands-hundreds digits bus-bars (not shown) assigned to thousands-hundreds digit combinations the irst digit of each ot which is 5. Likewise, tube 24, one of whose elements is connected to bus-bar TH52, has its other element connected to the hundreds digit bus-bar H2, to which are also connected corresponding elements of tubes associated with others of the 100 thousands-hundreds digits bus-bars (not shown) assigned a. thousands-hundreds digit combinations the second digit of each of which is 2.

The 100 thousands-hundreds digits bus-bars TH00 T1199 are each supplied with negative potential from negative battery B1 through, for example, resistor 31 connected to bus-bar THEM, resistor 32 connected to busbar TH41, resistor 33 connected to bus-bar TH52 and resistor 34 connected to bus-bar TH99. Each of the otice OPEL, thousands digit TH- and hundreds digit H- bus-bars is supplied with a higher negative potential from negative battery B2 through resistor 35, for example, connected to bus-bar OFFL, it being understood that there is one such resistor connected to each of the several mentioned bus-bars and to battery B2. The difterence of potential between batteries B1 and B2 is slightly lower than that which is necessary to maintain conduction in each tube, such as tube 19, for example. None of the gas discharge diode tubes connected to the busbars, therefore, normally conducts, but will conduct if the difference of potential between their elements is Y slightly increased.

Owing to they arrangement of gas discharge tubes between the sleeve conductors of lines and the thousandshundreds digits bus-bars Tlititl T1199, and between the latter bus-bars, the 10 thousands digit busbars THO 'TI-I9, and l0 hundreds digit bus-bars H0 H9, it should be evident that if a potential is applied to the sleeve conductor of any line, conductor 14 of line 12, for example, which is sufficient to cause the starter anodes of the gas discharge tubes Connected thereto, in this instance tubes 17 and 18 to conduct, the main anode supply to said tubes from bus-bar RP will impress positive pulses of a half cycle duration on bus-bar TH41 (and also on bus-bar TU67), and the voltage resulting therefrom will be transmitted through tubes 25, 26 and 27 to the bus-bars OFF1, T114 and H1, respectively. This, however, will occur only it the pulses received over the sleeve conductor 14 from the identier circuit in Fig. 3 are in the ring party phase; that is to say, coincident in time with the occurrence of the positive pulse of a half cycle duration applied toV conductor RP, as will be explained. On the other hand, if two pairs of tubes are connected to the sleeve conductor, as is the case for example with tubes 15, 16 and 150, 151 connected to sleeve conductor 13 of line 11, and the main anodes of one pair of tubes are connected to bus-bar TP, as they are for the tubes 150 and 151, said latter tubes will not conduct at the time that tubes 16 and 15 are caused to conduct by the pulse transmitted over the conductor RP, since the starter gap breakdown in tubes 159 and 151 would occur at a time when their main anodes are negative since the pulse applied to conductor TP is negative when the one applied to conductor RP is positive, and vice versa. lf suitable indicating means are provided, the presence of potential on bus-bars OFF1, 'TI-I4, and H1 when tubes 25, 26, and 27 are rendered conducting, will indicate that the station B on line 12, to the sleeve conductor 14 of which potential was applied, is in otiice No. l, that the thousands digit of said stations directory number is 4, and that the hundreds digit is 1.

It is also evident that a set of thousands-hundreds digits bus-bars TH00 TH99 and an oce bus-bar,

arcanes such as bus-bar 'OFI-T1, may be provided `foreach -central cnice, since these 'bus-bars are use'd to lindicate rthe central oiice in which the line being identified .is located. The 10 thousands digit `bus-bars TH() TH9 and the l hundreds digit bus-bars H0 H9, however, may be used to serve the lines of any number of central oices, since these bus-bars are used only to indicate `digits of directory numbers.

.A similar arrangement as above of bus-bars and `gas discharge tubes is used for .producing aniindication of the tens and units digits of directory numbers; The cathode of the second of the abovementioned gas discharge `triode tubes associated with the sleeve conductor of each line for a subscribers station thereon is connected to one of '100 tens-units digits bus-bars TU() TU99, of which bus-bars TUili, TU38, TU67 and T99 are four, in accordance with the tens-units digi-ts combination of the directory number of said station. For example, the cathode of tube 16 associated with line 11 and ring station `A thereon having the directory number 5238, is connected over conductor 36 to busbar TU3S, to which are also severally connected the cathodes of tubes (not shown) associated with other stations, the directory numbers of which comprise the tens-units digit combination 38. The cathode of tube 151 of the pair of tubes 151 4and 150 also associated with line 11 but with the tip station C thereon having the directory number 0099, is connected over conductor 152 to bus-bar TU99, to which are also severally connected the cathodes of tubes (not shown) associated with other stations the directory `numbers of which comprise the tens-units combination 99. ln a similar manner, the cathode of tube 1S, associated with line 12 and the individual station B thereon having 'the directory number Ll-167, is connected 'over conductor 37 to bus-bar TU67, t'o which are also severally connected the cathodes of tubes (not shown) associated with 'other stations, the directory numbers of which comprise the tens-units digit combination 67.

To each of the 100 tens-units digits ,bus-,bars TUM) T`U99 is connected one lelement of each of two gas discharge cold cathode diode tubes. For example, one element of each of tubes 38 and 39 is con vnected to bus-bar TU99, one element of each of 'tubes dit and 41 is vconnected to bus-bar TUtl, one element of each of tubes 32 and 43 is connected to bus-bar TU38, and one element of each of tubes 44 and '45 is connected to bus-bar TUtiil. The other element of `one of the tubes associated with each tens-units digits busbars TUtld TU99 is connected to one of 10 tens digit bus-bars Ti? T9 in accordance with thetens vdigit of the tens-units digits combination of' 4the vinvolved station directory number, and the other element of ythe `,second tube associated with each tens-units digits bus-bar is connected to one of A units digit 'busbars UG U9 in accordance with the units digit 'of said combination. For example, tube having one ot' its elements connected to bus-bar 'TU67 for the tens-'unit :digit combination 67, has its other element connected to bus-bar T6, to which are also connected corresponding elements of tubes (not shown) associated with the other of the 100 tens-units digits bus-bars TUM TU99 assigned to digit Vcombinations each of whose tens digit is 6. Likewise, an element of `tube 41, `also yassociated with bus-bar T1167 and assigned to the same tens-units digit combination 67, is connected `to said bus-bar TU67, While its other element is connected to units bus-bar U7 to which are also connected corre spending elements of tubes (not shown) associated with others of the 100 tens-units digits bus-bars TUti) 'IF-U99 assigned to tens-digit combinations each of whose units digit is 7.

Each bus-bar is supplied with suitable potential, the y1.00 tens-units digits bus-bars TUGGJ TU99 each being supplied with `negative ,potential v,from battery B3 through resistors, `such as resistor 46 Fior bus-bar T1167, and `the tens digit and units digit `bus-bars Tt? T9 and Ut) U9, respectively, with higher negative potential from battery B4 through resistors such as re sister 47 for bus-bar U0, such that the gas discharge diode tubes severally connected between the tensunits busbars TUllt f. TU99 and the `li) tens busbars T0 T9 and the 10 units bus-bars U0 U9 .do not normally conduct, but will conduct 4if the potential difference between their elements is slightly increased.

Y lt is evident `that if a potential is applied to the sleeve conductor of any line suiiicient to cause the starter anodes of the gas discharge tubes connected thereto to conduct, and if such 1starter anode conduction occurs when the main anodes of said tubes have a positive pulse applied thereto over conductor TP or RP accordingV to which ot' said `conductors said main anodes are connected, conduction will spread through the main gaps of the tubes, causing Vpotential to be present on `the bus-bars to which the cathodes of said tubes are severally connected. The presence of `potential on the bus-bars associated with the tube having its cathode connected to the bus-bar in the tens-units group of bus-bars T U0@ TU99 which indicates the tens-units combination of the directory number, will vindicate the tens and `units digits of the directory number of the calling station on .said line. For example, if potential is applied to `sleeve conductor 14 of `line 12, causing tubes i3 `and 17 to conduct when a positive `pulse is applied to conductor RP, potential will be present on bus-bar TU67, thence to tubes 4i) and 41, causing said tubes to conduct, and through said latter tubes Ato bus-bars T6 and U7, indicating by the electrical lactivation of said latter two barsthat the tens and units digits of the directory number of the `station `ou line 12 are 6 and 7, respectively.

it is also evident `that the 1GO `tens-units digits bus-bars TUtlil T3399, the l0 tens digit bus-bars T0 T9, and `the 10 units digit bus-bars U0 U9 may be used to serve any number of lines located in any number oti central ofces, since said bus-bars are Aemployed to indicate `digits of directory numbers of lines irrespective of the 4central oices in which said lines are located.

By the use of `additional bus-bars and additional gas e discharge tubes connected in the manner described, `the system may be extended to provide means for indicating directory Vnumbers of more than four digits, or other information in regard `to a line or station to be identified, such as, for example, the `class of the line or its rate zone.

For utilizing the means provided by the common circuit network shown in Figs. ,-1 and 2 for identifying the directory number of a. calling station, an identier circuit shown in Fig. 3 `is employed. This -identifier comprises an indicating tube and an associated `registering tube connected through a condenser to each of the oiice OFF- thousands digits Tielt) TH9, hundreds digits Ht) H9, tens `digits Tt) T9, and units digitsUt) U9 busbars, a pulsing tube 56, and suitable registers for the office digit and for each `of the four digits of the directory number. For example, tube 4S is an indicating tube and tube 49 is a registering tube, both associated with thousands digit bus-bar THS; tube ,Sil is an indicating tube and tube 51 is a registering tube, both associated with hundreds digit bus-bar H2; Vtube 52 is an indicating tube and tube 53 is a `registering tube, both associated with tens digit bus-bar T3, while tube 54 is an indicating tube and tube 5S is a registering tube, both associated with units digit bus-barUB. The indicating and registering tubes for an oiiice bus-bar are not shown. Tube 56 is, as `said before, the pulsing tube of the identifier, and has one of its control grids and cathode connected as shown to the main anode of each Aof `the indicating Vtubes associated with each of the digital bus-bars OF5-f, THO...TH9;H0...H9;T0...T9;andU0...`U9.

In the present embodiment of the invention, the indicating tubes and the registering tubes are gas discharge triode tubes of the cold cathode type, while the pulsing tube 56 is a gas discharge tetrode tube of the heated cathode type. The registers may be of any suitable type and may each be similar to the register for the units digits, comprising the ten relays R9 R9, and relays CK and ON as shown in Fig. 3.

The control anode of each of the indicating tubes, for example tube 54, is supplied with positive potential by positive battery through resistors 57 and 5S, and this potential is of such value that said tube will not normally conduct even when its main anode is also supplied with positive potential, but will conduct if, at the same time, Ythe potential of its control anode is slightly raised. The main anodes of all the indicating tubes of an identifier, such as tubes 48, 5d, 52 and 54, for example, are connected, as said before, to the cathode and control grid .of theA associated pulsing tube 56, the anode of which is supplied with rectiiied but unfiltered full wave alternating potential from the source 59 through transformer dit and rectiiers 'VR-3 and Vil-4. The other control grid of saidtube is biased by negative battery through resistor 61, so that said tube does not normally conduct, but will conduct if the potential of said other control grid is made slightly less negative, say by a positive pulse over conductor 116. The main anode of each of the registering tubes, for example, tube 55, is supplied with positive potential as shown, and the control anode is biased by potential from the voltage divider composed of resistors 62 and 63, so that said tube does not normally conduct, but will conduct if its control anode is made slightly more positive.

To identify the directory number of a station on a calling line, for example the ring station A on line 11, and having the directory number 5238, said line is extended in the manner common to cross-bar systems by the line link d4, the junctor 65 and trunk link 66 to the trunk 153. This trunk may be of any suitable kind that is equipped with a party test circuit including the relay TP by which, when appropriate, said relay is bridged across the line extension to determine whether, on a twoparty line, the tip station or the ring station has initiated the call. It it is the tip station, `for example station C, relay TP operates, but if it is the ring station, for example station A, or an individual station, for example station B of line 12, relay TP remains normal. Patent No. 1,513,351, granted October 28, 1924 to D. M. Taggart et al. shows one suitable embodiment of this party test circuit, the relay 24g therein corresponding to relay TC of the present application, reference is made to this patent for a complete disclosure and description of the manner in which said circuit operates.

The trunk 153 is connected to the identiiier of Fig. 3 by means of the usual identifier connector mechanism (not shown but indicated in Fig. l) which, of course,

has access to other trunks as well, only the conductors TF1 and 68 of the trunk indicated in Fig. l being shown as extended to the identifier, since these conductors are the only trunk conductors involved in the operation of the present invention. it is evident that when by the operation of the identiier connector the identiiier shown in Fig. 3 is connected to the trunk 3.53, the operation of relay Ti in response to the party test, and indicating that the call was initiated by the tip station C, will ground conductor TF1 and thereby complete the circuit of relay TP--A, causing said relay to operate. if the call was initiated by the ring station A, or by an individual station if the connection `was from an individual station, relay TP would remain normal as a result of the party test, and relay TP-A would not be operated, it should be noted that relay TiJ--A is individual to the identifier shown in Fig. 3, relays TP-B, TB-C and TB-D shown in Fig, 4, each being individual to another identi- The cathode of the pulsing tube 56 of the identifier shown in Fig. 3 is connected through resistor 67 and conductor 68 to sleeve conductor 13 of the line 11. By suitable means such as that hereinafter described, the control 'grid of tube 56 is made momentarily sufficiently less negative to cause said tube to conduct during the one-half of one cycle of alternating current.

The sleeve conductor of a subscribers line, for example conductor 13, is used in automatic telephone systems for other purposes, chief among Which is the holding of the magnets or' the various switches by which the line is extended. Rectifier 69 furnished in the trunk, provides a path to ground for the negative potential by which said magnets are held, but opposes the passage of positive potential. The positive pulse from the cathode of tube 5d, when it occurs, will not, therefore, pass through rectiiier 69 but will be transmitted to sleeve conductor 13 as extended to conductor 68, and to tubes 15, 16 and 150, 151 causing either pair of said tubes to be rendered conducting depending upon which pair has the positive phase of the potential supplied to the anodes thereof over conductor TP or RP which coincides with the positive pulse transmitted over the sleeve conductor 13. It it is assumed, for example, that the ring station A has initiated the call, then it will be shown that when the positive pulse is transmitted over the sleeve conductor 13, a coincident phase of potential appears on conductor RP, causing tubes 15 and 16 to be rendered conducting, thence by the conduction of tube 15 to bus-bar THSZ and by the conduction of tube 16 to bus-bar TU33. The pulse ot positive potential on bus-bar THE?. will cause tubes 22, 23, and 24 to conduct. By the conduction of tube 22 the pulse will be transmitted to bus-bar GFFl; by the conduction of tube 23 it will be vtransmitted to bus-bar THS, and by the conduction of tube 24 it will be transmitted to bus-bar H2. Likewise, the positive pulse on bus-bar TU33 will cause tubes 42 and i3 to conduct. By the conduction of tube 42 said positive pulse will be transmitted to bus-bar T3, and by the conduction of tube i3 it will be transmitted to bus-bar U8.

The positive pulse on bus-bar U8, for example, will be transmitted over conductor 70, and will produce a pulse through condenser 71 the magnitude of which will depend upon the rate of change in potential of the pulse as applied to said condenser. The pulse from condenser 71 is then transmitted through resistor 57 to the control anode of tube 54, causing said tube to conduct momentarily since, at the same time a pulse of positive potential 1s received on the main anode of said tube from the cathode of tube 56, the same pulse is simultaneously transmitted to the main anodes of the indicating tubes, including tubes 48, 50, 52 and 54. The rise of potential at the cathode of tube 54 due to the conduction of said tube 56 will be transmitted through condenser 72 to the control anode of tube 55, causing said tube 55 to conduct over a circuit extending from positive battery, through the anode-cathode space thereof, resistance 73, No. l normal contact of relay R8, and the Winding of said relay, to negative battery.

In like manner, the positive pulse on bus-bars OFFI, THS, H2, and T3 will each cause conduction ofa tube (not shown) similar to register tube 55 which is associated with bus-bar OFF, and of tubes 49, 51 and 53. Conduction of said tube (not shown) associated with u bus-bar @FP1 indicates that line 11 is in oiice No. l,

while conduction of tubes 49, 51, 53, and 55 indicate that the four digits of the directory number of station a on line 11 are 5, 2, 3, and 8.

The indication given by the conduction of each of the registering tubes, for example tube 55, may be registered by any suitable means, for example, the relay circuit such as shown in Fig. 3 for registering the units digit indication. Only three register relays Ril, R8 and R9 of said circuit are shown, but it will be understood 9 @that .the y:circuit comprises .ten -such relays R R9, oach-connected to a corresponding register tube .in the mannershown for relay R8 and tube 55.

`The current which `normally flows from positive bat- .tery-thr-.ough resistors `62, 63 and 73, No. .1 normal.con .tactS-ofirelayRS, and the `winding of said relay to nega- 4tive battery, is notsufiicient to operate relay R8. However, when Atube .55 conducts, as described above, the decreased resistance in the circuit causes additional current to flow, operating .relay Ril, which locks up through its No. l .rfront contact and No. 2 contacts of `normally operated relay ON. The operation of `relay R8 opens tat the No. :l fnormal contact the circuit `of tube 55, caus- .iug tsaid tube `tocease .to conduct and, at the No. 3 back contactfofzsaid relay, opens the normal operatingicircuit r,of relay N, which circuit extends from battery through 'the winding of relay ON, and No. 3 back contacts of relaystRl) to R9, inclusive (relays Rd, R8, and .R9 only `tbeing shown.) to iground. However, relay CK now operates `rover a .circuit iextending `from battery through the winding :offsaid relay .-No. L2 contacts of relays .Ril to R9 `(relaylf) only :beingzshou/n), No. 3 .front contact of relay SRS and No. `3 back contact of relay R9, `to ground, providing :an obvious :additional circuit through `its contacts for relay ON which prevents the .release thereof.

If, :through some .fault in the crcuits,t1nore `than `one of :the register relays VRt) to R9, for example, are operated `iat the same time, the `circuit of relay CK will not -be completed. `Relay CK will, therefore, .not operate, :and relay vON will release. A circuit will then be .com- -pleted :from .ground through back Contact of 'rela-y CK -an'cl No. lscontacts of :relay ON toan alarm (not shownl) urotuatingxsaid alarm. l

.A .plurality `of :identifiers lof `the `type shown in Fig. .3 and 'described above :may `be associated with the bus-bars shown in Figs. Al and 2. vIf vthe respective pulsing tubes 56 of zthese identifiers zare actuated repeatedlyand in vvsucfcession (as kwill .be shown), no `two pulsing tubes `being 'actuated at the same moment, `then .any or all `of Asaid 4identifiers :may be connected at .the same .time to calling ylines for .identification 4of the directory `numbers of their :respective calling stations, `and each identifier willidentify the station on the line to which itis connected.

.fior example, assume two identifiers rto Vbe :associated with the .units sdigit bus-bars U0 U9. To each .of -these bus-bars will be `connected two .indicating tubes similar to 'tube .54 `andin the manner shown .for tube .54. The main anode yof one of `said tubes associated With each bus-.bar ywill-be connected to the cathode of `a pulsing tube :56 .of .a .first identifier, while the main anode of :the .other of said -tubes associated with each busbar wi11 be `connected -to the cathode of a pulsing `tube 5o `associated the second identiiier. lf the cathode -of the pulsing ftube 56 of the firstidentifier be connected tothe extended sleeve conductor of a line .having `a directory .number fthe `units digit tof which .is 6, and the `cathode of :the pulsing tube .56 Tof .the 'second :identifier be .connected to `the texrtended sleeve conductor of a line .having a directory mum- `ber the units digit of which is "7, and the two ipulsing -tubes 56 are rendered momentarily conductive sin succestsion, ia positive pulse will appear on bus-bar U6 when .the pulsing tube 56 of the first identifier is renderedconducting land 'will reach both indicating tubes connected ,to :said bus-bar U6, while a positive pulse will appear on .bus-bar U7 when, later, the pulsing Vtube 56 of the second identifier is rendered conducting and will .reach both indicating tubes connected to said bus-bar U7. But the firstmentioned positive pulse Will affect only the first of lthe tw'o iindicating tubes connected to bus-bar U6, since the main anode of said tube is, at the moment, supplied with potential from the cathode Vof the pulsing tube 56 `foi? the first identifier, while the main anode of the second "indicatingftube `is 'not supplied with potential. Likewise, lthe second-'mentioned positive pulse `will `affect only the V'secondfof -the two indicating tubes 'connected to bus-bar U7, :since the main anode of said `tube iis, atthe moment, supplied with potential from the cathode of thejpulsing tube 56 nof the 'second identifier, While the main anode of .the .first indicating `tube is not supplied with potential. yln like manner, `other indicating tubes, and `consequently' the associated registering tubes, are affected by pulses produced by the associated pulsing tube 56, `but are un* affected by lpulses produced by thepulsing tubes of other identifiers.

A circuit arrangement `for actuating four identifiers, `for example, in rapid succession for the purpose described above is yshown yin Eig. 4. it includes a pulse generating tube Maud a `circuit of the type `known as a thyratron ring, comprising tubes HA, B, 76A, 75B, 377A, 71B, 78A`and 78B. This circuit 4is arranged for actuating Vfour identifiers but, by extension of the thyratron ring, `may be adapted to the actuation `of any number of identifiers.

` 011e secondary winding of transformer `iid is supplied withdouble.frequencyalternating current from the supply source 59 over conductors Si, d2 by a frequency `doubler circuit FD of `the well-known type, `said source 59 also supplying, of course, anode `potential to pulsing tube 56 and to :identical pulsing tubes 55 (not shown) of the three other :identifiers to be actuated. Alternating potential from the other secondary winding of transformer 84) `is biase Aby negative potential from the voltage `divider composed :of resistors 83 `and lid, and supplied to the network composed of resistor 85 and condenser 86. The values of said resistor and condenser are so chosen that the potentials at rectifiers 37 and have a phase dilerence of nearly, butnot exactly, degrees.

Curves A and B in Fig. 5 show graphically the relative potentials applied to rectifiers 3"? and respectively. lSaid .rectiiiers are .sopoled that they oppose transmission of ,positive potentials. The resultant potential transmitted ,through rectifiers d'7 `and and thence through ren s'istor S9 to the control grid of tube "id, which, `in the ,present embodiment .of the invention is a gas discharge .triode ytube of .the heated cathode type, is shown by the lheavy .line curve Vof Fig. .5. lt will be observed that said control gridis .maintained sufiiciently negative to prevent conduction in tube 74, except duringa `short period in `each cycle when itspotential approaches zero sufficiently `to permit tube ,'74 to conduct. The anode of tube .'74 is `supplied with operating potential through the self-clear- .ing anode circuit comprising resistor 9b and condenser .91, `the values of which are so chosen in relation to the value of the yanode rpotential and the characteristics of tube 74 that .the discharge of condenser 91, due to the drop .of potential through resistor 94% when tube 74 conducts, `maintains conduction until the control grid of `tube `74 again goes negative, when the potential between the anode `and the cathode of said tube is insufiicient, due to thepotential drop finresistance 9d, to maintain conduction.

-Tube 74, therefore, conducts for a very short period in each .cycle of alternating current, producing at its cathode short positive pulses which are transmitted vthrough. resistor .92, .thence through condensers 93A, 93B, 94A., 94B, 95A, 95B, 96A, 96B, and resistors 97A, 97B, 98A, "98B, 99A, 99B), ltlflA and itltt to the control anodes of the gas discharge cold cathode triode Atubes 75B y75A .(reading to the right consecutively from tube 75B to and including 775A). The control anodes of said tubes are each negatively biased. For example, the control anode of `tube 75B is biased by negative battery `through resistors itil, HD2, and 97A. The amplitude of the pulses fromthe cathode of tube 7d is limited by rec tier `103 to a `value linsufiicient in itself to overcome .said .negative lbias and cause tubes 755A 73E? to conduct. However, upon the `closure of switch .104i to apply anode 'potential x,to `said tubes 75A 73B the sudden rise of potential at the main 'anode of tube 75A is transmitted through Icondenser 105 to the control anode or said tube, the current path `being completed through. resistors IWB, `15'6, yand L1'55, to negative battery.

The conductivity of tube 75A raises the potential of its cathode, and the rise in said potential is made available as a positive pulse at the back contact of relay TP-A if this relay is normal at the time; that is, if the calling station is an individual or ring party station as before described. becomes etective at this time over conductor 116 to over come the bias at the control cathode of tube 56 effected by negative battery through resistor 61 which, as said before, keeps said tube 56, inactive. The application of the pulse renders the control grid positive, thereby causing said tube to become conductive, thereby to cause a positive pulse to be applied to the anodes of the indicating tubes and a positive pulse to conductor 68 (or sleeve'conductor S of thev line) and thence to conductor 13 of the line of the calling station. It should be noted at this time that conductors 81 and 82 are so wired to the primary winding of transformer TR-Z that when, for example, conductor 81 is positive and conductor RP accordingly becomes positive, the pulse from tube 74 in consequence thereof is the pulse which renders tube 75A conducting and the latter etective in rendering tube 56 conducting. Fig. shows the phase relationship between the sixty-cycle potentials on conductors RP and TP, and

the impulses which advance the counting chain in Fig. 4,

this relation being assured by the suitable design of the frequency doubler circuit FD shown in said figure. The consequence is that if relay TP-A is normal when tube '75A is activated the line tubes 15 and 16 associated with the calling station A on said line will be rendered con.- ducting since at the time that the positive pulse is being supplied to conductor 13 of said line by the conductivity of tube 56, a coincident positive pulse is being supplied to conductor RP and to conductor 81 from the lower secondary winding of transformer 60. The indication of the directory number will then take place as already described.

It is apparent that if at the time tube 75A has been rendered conducting relay TP--A is operated, owing to the fact that the call is initiated by the tip party A, then no pulse would be applied to conductor 116 and pulsing tube 56 would remain quenched.

Said pulsing tube 56 would then be operated upon the operation of tube 75B, the next tube in the thyratron chain, the operation of which is brought about as follows:

A part of the resultant rise in potential at the cathode of tube 75A, the amount being determined by the voltage divider composed of resistors 101 and 110 is transmitted through the network composed of resistors 102 and 97A and condenser 111, and with a time delay due to the characteristics of said network, to the control anode of tube 75B, raising the potential of said control anode so that the additional potential of the next positive pulse from the cathode of tube 74 will be sufficient to cause tube 75B to conduct. The resultant rise in potential at the cathode of tube 75B is available at the front contact of relay TP-A. Should this relay be operated in consequence ot' the fact that the call was initiated by the tip station C, then the pulse is transmitted over conductor 116 to cause the operation of tube 56 at the time when a positive pulse is being concurrently applied to conductor TP from the upper secondary winding of transformer 6U, thereby to cause tubes 150 and 151 associated with. station C to operate, with the results already noted.

Thus the circuit of Fig. 4 provides two time-spaced impulses (time slots) for each identicr with which to enable it to identify a particular number, using the rst impulse to identify such a number if it is that of an individual or ring party station, and the second (and later) impulse if said number is that of a tip party station.

The resultant sudden rise of potential at the cathode of tube 75B is transmitted through condenser 106 to the V cathode of tube 75A, raising the potential of the cathode lf relay TP-A is normal, the positive pulse.

composed of resistors 112 and 113, is transmitted through the network composed of resistors 114, 97B and condenser and with a time delay due to the characteristics of said network to the control anode of tube 76A so that, upon receiving the next positive pulse from the cathode of tube 74, tube 76A conducts, causing conduction in tube 75B to cease and preparing tube 76B for conduction on the next pulse from tube 74 in the manner described for tube 76A.

This action is repeated, tubes 76B, 77A, 77B, 78A, 73B, 75A conducting in succession indefinitely. Each time tube 75A conducts, for example, a positive pulse is produced at the cathode of said tube which, if relay SP-A is normal, is transmitted over conductor 116 to the control grid of pulsing tube 56 individual to the identifier shown in Fig. 3, actuating said tube in the manner previously described, and each time tube 75B conducts, a positive impulse is produced at the cathode of said tube which, on the one hand, is effective in extinguishing tube 75A and, on the other, is transmitted over conductor 116 if relay TP-A is operated, to actuate tube 56, to produce a positive pulse over the sleeve conductor 68 if such a pulse was not previously produced when tube 75A was conducting because of the operated condition of tube 75A.

It is evident since relays 'TP-B, TP-C and TP- are severally associated with three other identiers, positive pulses being produced in succession by each of the pulsing tubes 56 of said identifiers when, in the appropriate order and time a pulse is applied over conductor 117 when tube 76A is operated and relay TP-B is normal or when tube 76B is operated and relay TP-B is operated, over conductor 11S when tube 77A is operated and relay TP-C is normal or when tube 77B is operated and relay TP-C is operated,l and over conductor 119 when tube 7SA is operated and relay TP--D is normal or when tube 78B is operated and relay TP-D is operated. The cathode of tube 56 and similar pulsing tubes of said other three identiers need only be connected to the extended sleeve conductors of lines, as previously described, during a period suicient for each of said tubes to receive one pulse to identify the number for each of the stations on said lines.

A large number of lines are dependent for identication upon the potentials supplied to the bus-bars for actuating the gas discharge diode tubes connected therebetween. Therefore each bus-bar should be provided with an alarm circuit to give immediate warning of the failure of any of said potentials. Suitable alarm circuits are disclosed in Fig. 2. Each of the thousands-hundreds digits bus-bars THQ-t9 TH99 and each of the tensunits digits bus-bars TUttl TU99 may he provided with an alarm circuit similar to that shown, as an example, associated with bus-bar TU67. The main anode of tube which, in the present embodiment of the invention is a gas discharge triode tube of the cold cathode type, is supplied with alternating potential from the source 121 through the Winding of relay A1, while the cathode of said tube is supplied with positive potential directly applied thereto. The difference of potential between the anode and the cathode of tube 120 is at no time sufcient to .initiate conduction in said tube, but is sufficient to maintain conduction on negative cycles of alternating current. Negative potential applied through resistance 46 to busbar TU67, thence through resistances 122 and 123 to the control anode of tube 12'@ causes said tube to conduct on negative cycles of alternating current, operating relay A1 The discharge of condenser 124 through resistance 122 maintains the control anode of tube 120 sufficiently negative when positive pulses are received on bus-bar TU57 so that tube 12d does not cease to conduct during the period of said pulses. If, however, the negative potential through resistance 46 should fail, tube 120 will cease to conduct, releasing relay A1, which completes a circuit to an alarm (not shown) actuating said alarm.

Each of the oiiice OFF-, thousands digit THU TH9, hundreds digit Hi) H9, tens digit T T9, and units digit Uit U9 bus-bars may be provided with an alarm circuit similar to that shown, as an example, associated with bus-bar Ut). Tube'125ywhich in the present embodiment of the invention is a gas discharge triode tube ci the cold cathode type, is supplied with anode potential in a manner similar to tube 120, its cathode being connected to ground.- Negative potential through resistance Lito bus-'oar Uh, thence through resistance 127 to the control anode of tube 125 causes said tube to conduct on negative cycles of alternating current, operating relay A2. Positive pulses received on bus-bar U0 are insuiicient to overcome the high potential supplied by battery B4 to the control anode of tube 125. However, should the potential through resistance 47 fail, tube 125 will cease to conduct, releasing relay A2 which completes the circuit of an alarm (not shown) actuating said alarm.

All of the tubes shown in the present embodiment of the invention are of the gas discharge type. However, it will be apparent to one skilled in the electronic art `that other forms of tubes such as vacuum tubes or other discharge devices could readily be substituted to perform the functions ofthe tubes described.

What is claimed is:

l. In a telephone system, the combination with a line having a plurality of stations thereon and a device for each of said stations, of means responsive to a calling condition on one of saidrstations for applying a positive potential successively to each of said devices, means for determining which of said stations .is the calling station, and means controlled by said last-mentioned means for applying a positive impulse to the device of said calling station coincidentally with the application of said positive potential thereto, thereby to operate said last-mentioned device. y

2. A telephone system according to claim 2 in which the devices individual to the stations are gaslled electronic tubes.

3. In a telephone system, the combination with a line having two stations thereon and gas-filled electronic devices individual to said stations, of means responsive to a calling condition on one of said stations for applying a positive potential successively to the devices of each of said stations, means for determining which of said stations is the calling station, and means controlled by said last-mentioned means for applying a positive impulse to the devices of said calling station coincidentally with the application of said positive potential thereto, thereby to operate said last-mentioned devices.

4. In a telephone system, the combination of a line having two stations thereon, a pair of gas-filled electronic devices individual to each of said stations, each of said stations having an identifying designation composed of digits or characters, means responsive to a calling condition on one of said stations for applying a positive potential alternately to each of said pair of devices, means for determining which of said stations is the calling station, means controlled by said station-determining means for applying a positive impulse to the pair of electronic devices of said calling station coincidentally with the apdevices of said calling station.

6. A telephone system according to claim 4 in which said means responsive to theconductivity of said pair of electronic devices comprises a rst group of bus-bars to which said pair of electronic devices for each station is selectively connected according to certain combinations of digits or characters constituting a stations identifying designation, other groups of bus-bars, other electronic devices selectively interconnecting the bus-bars in the rst group which are connected to the electronic devices of the stations with bus-bars in said other groups according to the individual digits or characters in said designations, said other electronic devices being rendered selectively conducting by the potential made available on the busbars of the first group by conductive electronic devices individual to the calling station, and means including a register responsive to the selective operation of said other electronic devices for determining and registering the identifying designation of said calling station.

7. In a telephone system, in combination, lines each having a plurality of stations thereon, each of said stations having an electron discharge device and anidentifying designation, means for identifying the designation of each of said stations, said means comprising means responsive to a calling condition on one of said stations for rendering partially conducting all electron discharge devices severally belonging to the stations on the line containing the calling station, means for producing a plurality of time-spaced impulses, means for determining which of said stations is the calling station, means controlled by said calling station determining means for operating said impulse producing means to produce the one impulse individual to said calling station, means for applying said impulse to the electron discharge device of said station, thereby to render said electron discharge device fully conducting, and means responsive to the full conductivity of said electron discharge device for identifying the designation of said calling station.

No references cited. 

